At the age of twenty-nine Siddhartha Gautama, prince of a ruling house in Nepal, abandons the luxuries of home, and the affections of a wife and a young son, to become a wandering ascetic. He is following a pattern not uncommon in India at this time, when the rigidities of a priest-dominated Hinduism are causing many to seek a more personal religion. Only a few years previously, in a nearby district, a young man by the name of Vardhamana has done exactly the same - with lasting results in the form of Jainism. (The conventional dates for both men, revised by modern scholarship, have been a century earlier.)

Gautama differs from Vardhamana in one crucial respect. He discovers that asceticism is almost as unsatisfactory as luxury.

According to the traditional account (first written down in the 3rd century BC) Gautama follows an ascetic life for six years before deciding that a middle path between mortification and indulgence of the body will provide the best hope of achieving enlightenment.

He resolves to meditate, in moderate comfort, until he sees the light of truth. One evening he sits under a pipal tree at Buddh Gaya, a village in Bihar. By dawn he is literally buddha, an 'enlightened one'. Like any other religious leader he begins to gather disciples. He becomes known to his followers as the Buddha.

The Four Noble Truths and the Eightfold Path: c.424 BC

Gautama preaches his first sermon at Sarnath, about 5 miles (8km) north of the sacred Hindu city of Varanasi. In this sermon, still a definitive text for all Buddhists, he proposes a path to enlightenment very different from the elaborate ceremonies and colourful myth attached to the Hindu deities.

Gautama's message is plain to the point of bluntness, at any rate when reduced to a simple list - as it usually is in primers on Buddhism. He states that enlightenment can be achieved by understanding Four Noble Truths; and that the pain of life, with which the Noble Truths are concerned, can be avoided by following an Eightfold Path.

The four Noble Truths are that pain is inextricably part of mankind's everyday life; that our cravings of all kinds are the cause of this pain; that the way off this treadmill is to free oneself of these cravings; and that this can be achieved by following the Eightfold Path.

The Path encourages the Buddhist to live a virtuous life by following the 'right' course of action in eight contexts. Many of these are moral evils to be avoided (as in the Jewish Commandments). But the eighth step, 'Right Concentration', goes to the heart of the Buddhist ideal.

Right Concentration is described in Buddhist scripture as concentrating on a single object, so as to induce a special state of consciousness through deep meditation. In this way the Buddhist hopes to achieve complete purity of thought, leading ideally to nirvana.

Nirvana means 'blowing out', as of a flame. It is common to Hinduism and Jainism as well as Buddhism. But in the two older religions it leads to moksha, release from the cycle of rebirth, total extinction. In Buddhism it is a blissful transcendent state which can be achieved either in life or after death - and which is achieved by anyone who becomes Buddha.

The spread of Buddhism: c.380-250 BC

By the time of his death, at about the age of eighty, the Buddha's followers are established as communities of monks in northern India. Wandering through villages and towns with their begging bowls, eager to describe the path to the truth, they are familiar figures. But so are many other such groups, including the Jains.

The advance of the Buddhists beyond the others is largely due to the enthusiastic support of a king of the 3rd century BC. Asoka rules over much of the Indian subcontinent. His inscriptions, carved on pillars and rocks throughout his realm, bear witness both to the spread of Buddhism and to his own benevolent support of the Buddha's principles.

During Asoka's reign, and with his encouragement, Buddhism spreads to south India and into Sri Lanka. The latter has remained to this day a stronghold of the earliest form of Buddhism, known as Theravada (meaning the 'school of elders').

By the time of Asoka there is already a rival tendency within Buddhism, involving an elaboration of the Buddha's essentially simple message of personal salvation. The difference is similar to that between Protestants and Catholics at the time of the Reformation in Christianity. Compared to the puritan standards of Theravada Buddhism, the other sect - which later becomes known as Mahayana - introduces a catholic profusion of Buddhist saints.

Mahayana and Theravada

Mahayana means the Great Vehicle. Its adherents argue that this form of Buddhism can carry a greater number of people towards the truth than Theravada Buddhism, which they dismiss as Hinayana - the little vehicle.

The main distinction is that in Theravada the Buddha is a historical figure who by his example shows the way towards nirvana; the cult is essentially a human system of self-discipline, with no trace of a god. In the younger but larger sect there is still no god, but there are a great many supernatural beings.

In Mahayana the historical Buddha, Gautama, becomes the latest in a long line of past Buddhas. They exist in some place beyond this world, from which they can offer support. Also in that place are the Bodhisattvas, who have yet to begin the final human life in which they will attain enlightenment as Buddha. They too can help mortals who show them devotion.

In Theravada the nearest approach to worship is the veneration of relics of the historical Buddha, whose hair or tooth is made the central feature of a temple. In Mahayana, with its many semi-divine figures, there is opportunity for more varied, more popular and more superstitious forms of worship. It is well suited to become what it claims to be - the greater vehicle.

A religion for east Asia: from the 1st century AD

Buddhism is the first of the world religions to expand from its place of origin. It does so by two distinct routes.

Theravada Buddhism is carried eastwards into southeast Asia, in an upsurge of Indian trade from the 1st century AD. The merchants and sailors are either Buddhist or Hindu, and missionaries take advantage of the new opportunities for travel. As a result the kingdoms of southeast Asia, much influenced by the more advanced civilization of India, variously adopt Buddhist and Hindu religious practices. Which of the two prevails is often the result of the preference of a ruling dynasty. The areas which eventually choose Buddhism are Burma, Thailand, Cambodia and Laos.

Mahayana Buddhism travels by a land route. In the 2nd century AD northern India and Afghanistan are ruled by the Kushan dynasty, one of whose kings, Kanishka, is a devotee of this form of Buddhism. His encouragement of it has special significance, since his kingdom occupies a central position on the Silk Road - at one of its busiest times, when its caravans effectively link China with Rome.

The western influence on the Kushan region (also known as Gandhara) is seen in the famous style of sculpture which portrays Buddhist figures with the realism of Greece and Rome. Eastwards from Gandhara the trade route is soon dignified with spectacular Buddhist centres, such as Yün-kang.

Buddhism is well established in China by the 2nd century AD and coexists there, with varying fortunes, alongside China's indigenous religions - Daoism and Confucianism. By the 6th century its influence has spread through Korea to Japan. Here too it coexists, in a shifting pattern, with the earlier Japanese religion, Shinto.

The region which develops the most distinctive form of Buddhism lies between India and China, and receives its first Buddhist influences from both directions in the 7th century. This is Tibet. It will evolve an element of Buddhism unique to itself - that of a succession of reincarnating lamas, with the Dalai Lama as the senior line.

In India Buddhism flourishes alongside Hinduism for many years, but from about the 8th century it declines (though Theravada Buddhism finds a lasting home in Sri Lanka). The Mahayana version of the faith becomes gradually submerged by the older and more vigorous Hinduism. It has perhaps been too willing to accomodate new themes, influenced by India's bustling inclination to worship everything.

A weakened Buddhism proves no match for the arrival in northern India in the 10th century of rulers professing another vigorous faith, Islam. Buddhism becomes no more than a faint devotional presence at a few classic shrines. It is the only world religion to have withered in its birthplace.

Buddhist murals: 5th - 8th century

Monks and pilgrims play an important part in the practice of Buddhism. Both are attracted to caves in remote places. And the profusion of popular stories in Mahayana Buddhism (on topics such as the adventures of Buddha in his previous lives on earth) provides a rich source of material for narrative paintings on the walls of the caves.

Two places suggest more vividly than any others the vitality of Buddhist cave painting from about the 5th century AD. One is Ajanta, a site in India long forgotten until discovered in 1817. The other is Dunhuang, one of the great oasis staging posts on the Silk Road.

At Ajanta there are about thirty architectural spaces cut into a steep cliff flanking a ravine. Some are viharas, or monasteries, with cells for the monks around a central hall. Others are chaityas, or meeting places, with a small central stupa as an object for worship and contemplation.

The paintings range from calm devotional images of the Buddha to lively and crowded scenes, often featuring the seductively full-breasted and narrow-waisted women more familiar in Indian sculpture than in painting. The latest images are from the 8th century, after which the decline of Buddhism in India causes these remote and beautiful places to become gradually abandoned and then entirely forgotten.

Dunhuang, on one of the world's greatest trade routes, is an altogether busier place than Ajanta. Rather than thirty caves, Dunhuang has nearly 500 - known collectively as the Caves of the Thousand Buddhas. The murals span three centuries, from the 5th to the 8th AD. The images in the earlier caves (hollowed from the soft rock, as at Ajanta) show the influence of central Asia and even India - the regions from which Buddhism travels on its way to China - but the later paintings are fully Chinese in style.

The invention of printing is a striking achievement of Buddhists in east Asia. Korea takes the lead. The world's earliest known printed document is a sutra printed on a single sheet of paper in Korea in750.

This is closely followed in Japan by a bold experiment in mass circulation (precisely the area in which printed material has the advantage over manuscript). In768, in devoutly Buddhist Nara, the empress commissions a huge edition of a lucky charm or prayer. It is said that the project takes six years to complete and that the number of copies printed, for distribution to pilgrims, is a million. Many have survived.

The first printed book: 868

The earliest known printed book is Chinese, from the end of the T'ang dynasty. Discovered in a cave at Dunhuang in 1899, it is a precisely dated document which brings the circumstances of its creation vividly to life.

It is a scroll, 16 feet long and a foot high, formed of sheets of paper glued together at their edges. The text is that of the Diamond Sutra, and the first sheet in the scroll has an added distinction. It is the world's first printed illustration, depicting an enthroned Buddha surrounded by holy attendants. In a tradition later familiar in religious art of the west, a small figure kneels and prays in the foreground. He is presumably the donor who has paid for this holy book.

The name of the donor, Wang Chieh, is revealed in another device which later becomes traditional in early printed books in the west. The details of publication are given in a colophon (Greek for 'finishing stroke') at the end of the text. This reveals that the scroll is a work of Buddhist piety, combined with the filial obligations of good Confucian ideals: 'Printed on 11 May 868 by Wang Chieh, for free general distribution, in order in deep reverence to perpetuate the memory of his parents.'

The printing of Wang Chieh's scroll is of a high standard, so it must have had many predecessors. But the lucky accident of the cave at Dunhuang has given his parents a memorial more lasting than he could have imagined possible.

Buddhist banners and scrolls on silk: from the 9th c.

The cave discovered in 1899 at Dunhuang contains many Buddhist paintings on silk. The larger ones (mostly showing Buddha seated in paradise with attendant figures) are designed for hanging out on poles on special occasions. Some are almost two yards in height and more than a yard wide.

Narrower vertical images of dramatically painted figures from Buddhist mythology are intended as banners, to be carried in procession with silk streamers attached. Painting on silk remains a central theme of Chinese art. But this flamboyant public use of images, characteristic of Buddhism, subsequently gives way to the more discreet and private art of the Confucians.

New sects of Buddhism in Japan: 12th - 13th century

One of Japan's most famous monuments is a vast bronze sculpture at Kamakura. Known as Daibutsu, and cast in 1252, it depicts Buddha. But this figure seated in peaceful meditation is not the historical Gautama Buddha. He is Amitabha Buddha, known and revered in Japan as Amida.

The cult of Amida, also called 'Pure Land' Buddhism, is one of several new sects in Japan, mostly arriving from China, which become naturalized during the Kamakura shogunate. It is based on a sutra in which Amida, who has achieved enlightenment as Buddha, assures all those who adore him that they can live with him for ever in a pure land - a Promise made in the Sukhavativyuha Sutra.

Another foreign sect of Buddhism, which the Japanese make very much their own, is known in China as Chan and in Japan as Zen (both derive from a Sanskrit word meaning 'meditation'). Zen, reaching Japan from China in the 12th century, lays great emphasis on intuition, or finding the truth within oneself, but it also stresses the importance of discipline.

It appeals to the new samurai class (several Zen masters teach sword fighting), and at periods during the shogunate it becomes almost the state religion. Zen masters encourage some of the most distinctive cultural aspects of Japanese life, including the Tea Ceremony (closely linked with the tradition of Japanese ceramics).

The most aggressive of the Buddhist sects is the only one to have its roots entirely in Japan. It follows the teaching of Nichiren, a fiery prophet who spends much of his life in exile for his criticism of the shoguns in Kamakura. They favour the rivals on whom he pours scorn, the devotees of Pure Land and Zen Buddhism.

Like Old Testament prophets, Nichiren foresees disaster befalling his misguided compatriots. The Mongol invasion of 1274 is seen by many as the fulfilment of his prophecies. His passion inspires a sect which still has a considerable following in 20th-century Japan.

Buddhism today

Buddhism in its various forms remains the most widespread of the ancient religions in east Asia, where it numbers some 300 million adherents. The greatest concentration is in the historic lands of Theravada Buddhism - Sri Lanka and the three countries, adjacent to each other, of Burma, Thailand and Cambodia. Buddhists still practising in Mahayana regions (China, Tibet, Mongolia) have suffered greatly from the atheist creed of Communism. In Japan a majority still adheres to various forms of Buddhism.

During the 20th century the faith has also begun to spread to entirely new regions. There is now a significant minority of Buddhists in the United States and in Europe.